Taken from Anandtech here:http://www.anandtech.com/displays/showdoc.aspx?i=2904&p=15 but especially this part:
"Those looking for NVIDIA’s Vista 8800 GTX driver needn’t look any further than Microsoft’s booth at CES. All of the gaming machines at Microsoft’s booth were running nForce 680i motherboards with single GeForce 8800 GTXs, under Windows Vista. The machines were running Crysis and Halo 2, and actually ran reasonably well. Halo 2 was choppy at times and there were some visual bugs with Crysis, but the driver was working and is apparently stable.

We spoke to NVIDIA to understand why there isn’t a 8800 Vista driver currently and why we won’t see one until Vista’s launch. NVIDIA’s GPU drivers these days are made up of approximately 20 million lines of code, which as a reference point is about the size of Windows NT 4.0.

Because G70 and G80 are radically different architectures, they each require a separate driver. Combine that with the fact that Windows Vista has completely changed the driver interface, similar in magnitude to what happened between Windows 3.1 and 95, and you’ve got a “perfect storm” of conditions for driver development. The end result is that for Windows Vista, two 20M line drivers have to be completely re-written (one for G80 and one from all previous architectures). In other words, this isn’t a simple port, it’s a radical departure from the way things were written before.

There are other elements of Vista driver development that apparently require more work than before. DirectX 9, DX9 SLI, DX10 and DX10 SLI support is provided through four separate binaries, which increases the complexity of testing and the overall driver itself, whereas there was only a single driver in the past.

Interfaces for HD-DVD and Blu-ray video acceleration requires a lot more code than before, thanks to the support for a protected path for HD video under Vista. Supporting this protected path for HD content decode means that you can’t re-use the video part of your driver when developing a Vista version.

The last major difference between Windows XP and Vista driver development is that the display engine connecting monitors to the GPUs has been completely redone.

Initial investment in driver development under Vista takes up quite a bit of time, and now we understand a little more of why. While it would be nice to have one today, there’s always a tradeoff that has to be made especially when driver work this intense has to be done. Couple that with the recent launch of NVIDIA’s G80 GPU and the decision was made to focus on DX9 and XP drivers in order to make the G80’s launch as solid as possible, and commit to delivering an 8800 driver by Vista’s launch.

When the driver is eventually available NVIDIA expects performance to be at par, slightly slower or slightly faster than the XP driver. What we’ve seen thus far from other Vista drivers is that performance is slower almost entirely across the board. As stability is currently the primary goal for both ATI and NVIDIA, many compiler optimizations and performance tweaks aren’t being used in order to get a good driver out in time for Vista’s launch. "

20 million lines of code?? Man that's insane....

DarkJedi664

01-11-07, 10:32 PM

Well THAT was very intersting. I never expected these drivers to as complex as NT4! It's only 18 days away, I can wait that long, though it agony is killing me :( I miss glass so much :(.

I like it. The gadgets , when I first heard and read about them seemed so gimmicky. While using them they've proven to be pretty useful and genuine.

Ancient

01-11-07, 11:44 PM

That's telling me what piece of garbage is Vista.
Because an existing 20M line of code driver has to be re-written?

Do tell.

stevemedes

01-11-07, 11:48 PM

Jurassic Park's how computer system ran on what? About 2 million? :p

F_L_C

01-12-07, 01:15 AM

Interfaces for HD-DVD and Blu-ray video acceleration requires a lot more code than before, thanks to the support for a protected path for HD video under Vista. Supporting this protected path for HD content decode means that you can’t re-use the video part of your driver when developing a Vista version.

The last major difference between Windows XP and Vista driver development is that the display engine connecting monitors to the GPUs has been completely redone.

Stupid content providers and their fkn DRM. I just read an essay on how Vista content protection guidelines will increase the development time for drivers and just about everything else. Some of the capabilities of the DRM system on Vista are potentially very scary indeed.